A dispersive morph in the naked mole-rat
Abstract
CLOSE inbreeding is known for a variety of small mammal species1-4 for which a high probability of mortality during dispersal makes helping and delayed maturation a relatively secure fitness option5. Prolonged inbreeding, however, is usually associated with lowered fitness6,7, and it has been shown that most highly inbred small mammals8 and social insects9 have inbreeding-avoidance mechanisms that promote some degree of outbreeding. However, previous field and laboratory research on the naked mole-rat (Heterocephalm glaber) suggested that this cooperatively breeding rodent is highly inbred10-12, with new colonies forming by fission13. Here we report the discovery of a dispersal phenotype that may occasionally promote outbreeding in naked mole-rats. These dispersers are morphologically, physiologically and behaviourally distinct from other colony members. They are laden with fat, exhibit elevated levels of luteinizing hormone, have a strong urge to disperse, and only solicit matings with non-colony members. These findings suggest that, although rare, a dispersive morph exists within naked mole-rat colonies.
- Publication:
-
Nature
- Pub Date:
- April 1996
- DOI:
- 10.1038/380619a0
- Bibcode:
- 1996Natur.380..619O